Positioning connector for hack saw blades



Oct. 12, 1954 H. HARRISON 2,691,396

POSITIONING CONNECTOR FOR HACK SAW BLADES Filed June 26, 1950 2 Sheets-Sheet l INVENTOR HENRY HARRISON BYI' Wm? {MW ATTORNEYS Oct. 12, 1954 H. HARRISON 2,691,396

POSITIONING CONNECTOR FOR HACK SAW BLADES Filed June 26, '1950 2 Sheets-Sheet 2 INVENTOR HENR-Y HARRISON I BYMw/w,

ATTORNEYS Patented Oct. 12, 1954 ADES Henry Harrison, Port Washington, N. YL

Application-June 26, 1950, Serial No; 170,377

2 Claims.

This invention relates to an improved device including modifications thereof for holding hack saw blades, saw blades, knife blades and. other similar articles which must be longitudinally tensioned on a framework and which must be at the same time oriented about the line along which the tension is applied.

Although the prior art has developed many difierent means for mounting blades in a tensioned position oriented about the line along which the tension is applied, the common d=ifficulty encountered has been the tendency of these mounting devices to wear and allow an improper orientation with an objectionable twisting efiect along the length of the blade The usual type of attaching means provided comprises two members having fixed pins over which the blade may be hooked and a tensioning means, often a screw and nut arrangement, positioned for increasing the distance between the two pins. It is common in this type of device to? provide the pin carrying. members with flat guide surfaces substantially perpendicular to the pins. The purpose of these two surfaces is to position the blade about the axis along which tension is applied, In practice, however, the pins soon are worn down and the bladeis thereby prevented from seating snugly in a. flush position against the guide surfaces.

It is a principal object, therefore, of this invention to provide a simple, easily operated. attachment device unaffected by Wear which will hold a saw blade, hack. saw blade, knife blade or other similar article snugly and positively against the usual blade guide surface without the undesirable twisting effect usually occurring in similar devices.

In general, the principal object of this invention is accomplished in an article of the class described which comprises a frame, means for applying a tensioning force to a blade supported by the frame, and a blade positioning member provided with a blade engaging. surface by providing an improvement comprisin a hinge member having blade securing means at one end thereof, the other end being pivotall'y held by the tensioning means in a manner permitting movement of the hinge member relative to the blade engaging surface in a plane normal to this surfacewith the blade securing means extending through the plane of the same surface. As explained hereinafter, this arrangement permits a component of the tensioning force to act in a direction causing the blade to be urged against the blade engaging surface in a manner preventing the undesired twisting action of the blade: from occurring. t

In the accompanying, drawings:

Figure 1 is a perspective view of a hack saw incorporating: one form of the new and improved blade attachment device of: this invention;

Figure 2' is: an enlarged partial cross-sectional view taken along the right-hand side of the blade attaching and tensioning means of Figure 1';

Figure 3 is a partial elevat'ional view showing only the rightehand. side of a modified form of a blade attaching and tensioning means of this invention;

Figure 4' is a cross-sectional view of' Figure 3-;

Figure 5 is a partial elevational view showing; only the right-hand: side of a second modified form of a blade attaching and tensioning means of the invention; and

Figure 6 is a cross-sectional view of Figure 5.

Referring now to the form of the invention shown. in Figures 1- and 2, there is: seenfor the purpose of illustration a hack saw incorporating one form: of the blade attaching means of this invention. The invention is applicable, however, to other uses requiring the tensioning of a member between at least two points. This invention, therefore, is not to be limited only to hack saw devices but may be applied to" many devices requiri-ng the aforesaid tensioning and orientation.-

The numeral 1 designates the usual blade hold ing frame which comprises a hollow member 2 having: a handle 3 at one end thereof and at the other end a. locking pin 4 extending transversely to the axis: of the hollow member 2'. Extending downwardlyfrom the hollow member 2 at a position lying between the handle 3 and the pin 4 are two frame members 5- joined. at their ends 6 as by bendingone l'e'g 5 in overlapping relation to the other and securing the same thereto by welding or riveting and, thereby forming a flat sided opening I: or guide for a purpose which will be described later; A spacing member 8 is: provided between the members 5 above the opening 1 for reinforcing and retaining the members 5 in their spaced position.

On'eleg' of: a substantially L-shaped' adi ustab'le member 9' is providedfor telescoping within the hollow member 2 and the length of the frame I' may be extended or shortened by interlocking the notches Ill and the pin 4 at the desired position.

0n the other leg of the |..-shaped adjustable member 9 is attached a generally U-shaped bracket member I! fixed inpositionby means of 3 one or more rivets such as I I extending through both sides of the bracket and the adjacent leg portion. The bracket I2 so arranged provides an opening I having fiat sides which also act as guides as will be described later.

A bolt member I3 which is square in cross section at I4 and which has a flattened shank portion l4 extends through the opening I of the bracket member l2 and is provided with a head I5 larger in diameter than the width of the opening I. The bolt member I3 is thereby prevented from rotating by the interlocking fit of its square cross section in the opening I.

A tensioning member indicated as a whole at i6 having a longitudinal flattened shank surface ll at one end thereof and an intermediate squared portion I'I terminating in a square threaded portion I8 at the other end thereof extends through the fiat sided opening I with the squared intermediate portion |'I guided and held in position by the flat sides of the opening I. A wing nut I9 is provided for adiustably extending the tensioning member l6 toward, or drawing it back from. the bolt member I3.

The tensioning member I3 is provided with a hole 20 substantially at the outer end of its fiat shank portion I1 and the axis of this hole is substantially perpendicular to the plane of the flat shank portion. The member I6 is also provided with a second hole 2| spaced inwardly from the hole 20 and having an axis perpendicular to the plane of the fiat shank portion II. The hole 20 has a cylindrical wall as indicated in Figure 2, while the hole 2| has a frusto-conioal wall. The largest diameter of the hole 2| is on that side of the fiat shank portion |I upon which a surface of the blade 22 is to be placed. The flat shank I4 of member I3 is also provided with similar holes 23 and 2|.

As shown for the purpose of illustration in Figure 1, opposite flat sides of blade 22 lie against the fiat shank portions M of members I3 and H of member l6. This showing was made for the purpose of simplifying the illustration of the drawing. If desired, however, the member I6 may be removed from the opening I, rotated 180 and replaced within the opening so that only one surface of the blade 22 lies against the fiat shank portion M of member I3 and the flat shank portion I! of member I5 upon fixing the blade in assembled position.

For the purpose of attaching the blade 22 to the members I3 and It by means of holes 23 normally found in each end of the blade, there is provided a modified U-shaped hinge member 24. One leg 25 of this hinge member 24 is inserted in the hole 2| so that the outer end of the leg 25 is in a position adjacent the fiat surface M or H. An upset end 26 may be provided on the leg 25 for the purpose of retaining this leg within hole 2| in its respective member I3 or I5. In addition, a second upset portion or stop 21 may be provided at that end of the base of the U-shaped member 24 adjacent the leg 25 so as to prevent accidental withdrawal of the leg 25 from the hole 2| in member H3 or IS.

The other leg 23 of the U-shaped member 24 is inserted in the opening 2|! provided in each of the members I3 and I 6. This leg may be bent inwardly as shown for the purpose of frictionally holding the blade 22 in position and it may have serrations 29 on its inner surface for the same purpose.

The modification shown in Figures 3 and 4 comprises a lateral extension 30 of the inner edge of one of the legs 5 at a position adjacent the opening I formed therein by means similar to that described in relation to Figure 1. The free end 3| of this lateral extension 30 as shown in Figure 4 is first bent inwardly at 3| and then outwardly at 32 in order to provide a flat surface 33 lying substantially in the plane which is parallel to the plane of the frame I and passes through the longitudinal axis of the tensioning member 34. The tensioning member 34 is square in cross section and is provided with square screw thread means 35 at one end thereof and an extension 36 at the other end thereof having a hole 31 therein which is shown to be counterbored at 31A. A modified U-shaped hinge member 38 is provided having one leg 39 inserted in the hole 31 and the other leg 40, provided with serrations 4| or an inward bend if desired as explained supra in connection with Figures 1 and 2, extending outwardly and through a slot 42 provided in the end of member 3|]. As also provided in the modification of Figures 1 and 2, the free end of the leg 39 may be upset if desired at 4| and a further stop or upset portion 42 may be provided for preventing the hinge member 38 from being accidentally removed from member 34.

As will be apparent, the modification shown in Figures 3 and 4 may be utilized on the other end of a frame by merely providing an extension similar to 30 on the bracket member I2 and a head similar to IE of a diameter larger than the opening I in place of the screw threaded end and wing nut I9 of tensioning member 34.

The second modification shown in Figures 5 and 6 is similar to that shown in Figure l with the exception of a modified form of hinge device 43 and the rocking attaching means. This hinge device 43 is substantially L-shaped and is provided at the end of one leg 43 with an enlarged looped portion 44 having an opening 45 therethrough. A hole 46 is provided in the tensioning member 41 for the purpose of receiving a fixed rivet 48 or bolt or other fastening means extending through the hole 46 at one end a distance greater than the thickness of the enlarged portion 44 and having a head 43 sufficiently large in diameter for retaining the hinge member 43 in a rocking position upon insertion of the rivet 48 through the opening 45 as shown. At the free end of the tensioning member 41 is provided a slot means 50 for receiving the other leg 5| of the hinge member 43. Leg 5| may be serrated or bent inward slightly or both where it engages the blade 22 at 52.

This second modification can also be used on the non-adjustable end of frame I when wing nut l9 and thread 35 are replaced by a solid head like l5.

From the above description taken with the drawings, it is seen, for example, that in order to use the modification of Figures 1 and 2, it is only necessary to attach the blade 22 by means of a hole 23 in an end, thereof to the leg 28 of the hinge member 24 associated with tension member l3, attach the other end of blade 22 to leg 28 of hinge member 24 associated with tensioning member I6, and then tighten up on wing nut 59. When wing nut H! is tightened the two hinge members 24 through legs 28 apply a tensioning force to the blade 22. This force is directed from the point of contact of the leg member 28 and the blade 22 through the points of contact of the modified U-shaped hinge members 24 and their respective tensioning members l3 and I5. These second points of contact indicated at A, which act as simple rocking hinges,

are positioned well behind the first point of contact. Thus, the force applied to the-blade 22 by the hinge members 24 through their extended legs 28 is not entirely along the line of the length of the blade 22. There is a second directional component which will tend to pull the ends of blade 22 against the long flat shank surfaces 14 and 17. Since one major object of applying tensioning to the blade is to hold it straight, the amount of tension applied is usually quite large. Thus, the relatively small component of force not in line with the length of the blade 22 is sufficient to force the ends of the blade 22 snugly and positively against the respective fiat shank guide surfaces I 4 and i1 and retain these ends there in an oriented position and thereby prevent a twisting effect from occurring in the blade 22.

The two additional modifications are seen to operate in the same manner as described with reference to the modification of Figures 1 and 2. The second points of contact of the two additional modifications are indicated at B in Figure 4 and at C in Figure 6. Since these two points B and C are also positioned well behind the first points of contact, namely, between leg 40 and blade 22 of Figure 4 and leg 5| and blade 22 of Figure 6, it is seen that the directional component of force is also sufiiciently large in these modifications upon tensioning the blade to force the blade positively and snugly against the respective guide surfaces 33 and 53.

It will be noted that in all forms of the invention the hinge member which secures one end of the blade to the tensioning member also coacts with the latter to draw the blade against the fiat guide surface of the tensioning member when the parts are set up. Further, one end of the hinge member is shaped to engage the wall of the blade opening while its opposite end is provided with means which coact with complementary means on the tensioning member to provide a rolling contact of the hinge member with the tensioning member so that the hinge member is free to rotate in a plane normal to the blade.

It should also be apparent from the above that any combination of the various modifications shown may be used if desired. Further, some applications of this invention may require only a single such hinge tensioning and orienting means, in combination with a blade attachment of the fixed pin or other conventional type. Also, it is apparent that the various modifications shown are for the purpose of illustration only and it is to be understood that changes in the construction of these modifications may be made without deviation from the spirit and scope of this invention wherein I claim:

1. In a hacksaw, a substantially U-shaped frame, a blade, means connecting the blade to said frame, said means including an axially adjustable tensioning member connected at one end to said frame and having a flat blade engaging surface and longitudinally spaced transverse openings, one of said openings having a cylindrical wall and the other a conical wall, a hinge member having spaced angularly disposed end portions, one of said end portions being provided with means extending through the cylindrical wall opening and engaging the wall of an aperture in the blade for maintaining the blade in a fixed position, and the other end portion of the hinge member having an enlarged head and having a rolling contact with the wall of the conical opening.

2. In a hacksaw, a substantially U-shaped frame, a blade, means connecting the blade to said frame, said means including an axially adjustable tensioning member connected at one end to said frame and having a flat blade engaging surface on one side thereof and spaced transverse openings, one of said openings having a cylindrical wall and the other a conical wall, a hinge member having spaced angularly disposed end portions, one of said end portions having a serrated edge extending through said cylindrical opening and an aperture in the blade so as to move and maintain the latter in a fixed position, the other end of said hinge member having an enlarged head extending through the conical opening and having a rolling contact with the wall thereof, so that the hinge member is free to rotate in a plane normal to the blade, and said head being spaced from the end of the blade and disposed substantially perpendicular to the axis along which the tension is applied to the blade.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 292,176 Pratt Jan. 22, 1884 330,104 Fornamder Nov. 10, 1885 518,420 Moxley Apr. 17, 1894 558,781 Culver Apr. 21, 1896 973,431 Hoffmann Oct. 18, 1910 1,905,940 Lambert Apr. 25, 1933 1,949,196 Voulten et al. Feb. 27, 1934 2,580,896 Dohner Jan. 1, 1952 FOREIGN PATENTS Number Country Date 707,424 France Apr. 14, 1931 457,571 Great Britain Dec. 1, 1936 121,593 Sweden May 4, 1948 

